Machinery & Energetics

The article is devoted to one of the ways to solve the problem of eliminating vibrations of the load on a flexible suspension during the operation of slewing gear of the jib crane. The optimization task of the mode for starting the slewing gear of the jib crane has been solved upon the criterion of the root-mean-square value of the change rate of the elastic section modulus in the driving gear. The set task has been solved by using the variational calculus methods. The optimization criterion is represented in the form of an integral-type functional, which displays undesirable properties of the system; for this reason its value is reduced to a minimum. The solution of the task lies in functional dependences of the motion modes of separate links of the jib system at the starting section, which are represented in the graphic form. The obtained modes for slewing the jib system enable the elimination of vibrations of the load on a flexible suspension after the starting process, as well as the minimization of dynamic stresses in the driving gear and the metal structure of the crane. In addition, the optimal starting modes make it possible to increase the productivity and reliability of the crane operation. The most expedient duration of the starting process has been substantiated for the desired structural, kinematic and dynamic parameters of the jib system.
The results obtained in this research may be used in future for specifying and updating the existing engineering methods of the calculation of the slewing gear of cranes with the load on a flexible suspension (rope) both at the designing/engineering stages, and in the modes of the real operation

jib/tower crane, turning mechanism, load, dynamic load, minimization, criterion, optimization, oscillation, elastic moment, speed